ERROR when appending ArrayList.remove and ArrayList.set

Question

ArrayList<Integer> M = new ArrayList<Integer>();
ArrayList<Integer> V = new ArrayList<Integer>();

System.out.println("How many values? ");
Scanner in = new Scanner(System.in);
int noVal;
noVal= in.nextInt();

for(int cn = 0; cn < noVal; cn++){
    int intrare;
    System.out.print("Introdu elem " + (cn) +" ");
    intrare = in.nextInt();
    V.add(intrare);
}

in.close();

for(int cn = 0; cn < noVal; cn++){
    if(cn==0){ 
        M.add(0);
        continue;
    }
    if(V.get(cn)>= V.get(M.get(M.size()-1)) )
        M.add(cn);
    else{

        M.remove(binarySearch(V.get(cn), M.size(), M)); //here is the problem
        M.set(binarySearch(V.get(cn), M.size(), M), V.get(cn));
    }

}

It returns error when tring to remove and set. This is a piece from an algorithm for computing in nlogn the longest ascendind substring from V. Everytime it goes to "else", that's the error:

Exception in thread "main" java.lang.IndexOutOfBoundsException: Index: 1, Size: 1
    at java.util.ArrayList.rangeCheck(Unknown Source)
    at java.util.ArrayList.remove(Unknown Source)
    at SirMaximCrescator.main(SirMaximCrescator.java:37)

The binarySearch function is:

public static int binarySearch(int key, int size, ArrayList<Integer> data) {
    int low = 0;
    int high = size - 1;

    while(high >= low) {
        int middle = (low + high) / 2;
        if(data.get(middle).equals(key)) {
            return 0;
        }
        if(data.get(middle) < key) {
            low = middle + 1;
        }
        if(data.get(middle) > key) {
            high = middle - 1;
        }
    }
    return low;
}

Answer 1

I have not fully understood you algorithm, but the exception means that at a moment, M will have a size of 1 and your binarySearch method will return 1 ; so you will try to remove index 1 from M whereas it does not exist (there's only index 0).

It has nothing to deal with the M.set , the error occurs the line before.